Steroidogenesis

Autism Spectrum Condition is a neurodevelopmental disorder characterized by the core diagnostic criteria of social communication and interaction impairment and restricted and repetitive behavioral patterns. This review draft is intended as a narrative of the Androgen Theory of Autism which holds testosterone, primarily fetal testosterone, as a key factor influencing autistic development. Its purpose is to present an overview of evidence for testosterone's association with autism. As the proposed relationship between autism and testosterone involves the characterization of autism as an extreme of the male brain, necessary references are made to sexually dimorphic behavioral tendencies, neuroanatomy, and endocrinology to convey the possible role of androgens in autism. The starting point is a description of fundamental male and female cognitive and behavioral inclinations. Noting that autistic traits are observed as extremes of the male phenotype, gender-associated behavior is related in terms of its source organ, a sexually dimorphic brain; and the male-making agents of its cause, androgen hormones, are likewise discussed in order to explain certain differences among the sexes. Research applying this understanding of androgenic effects by exploring the connection of testosterone to autistic traits in different age groups, sexes, and medical conditions is then reviewed. Lastly viewed is both a cause and consequence of autistic traits, the autistic brain, with an overview of the homogeneity, heterogeneity, and possible intra-sexual dimorphic effects of steroids on autism spectrum conditions. (Insightful Addenda: 1) Bushby - Head Circumference and Height Correlations; 2) Daphna Joel - Brains are Intersex; 3) 5a Reductase Inhibitor - Finasteride/Propecia/Proscar - possible physical/physiological/psychological/emotional effects - reports of affecting libido/arousal/memory/mood&emotions (Merck acknowledged some effect(s) on labels in Eur/US) - lowers DHT synthesis from T - some reports of increased estradiol concentrations from resulting higher available T [Testosterone] and effects)

Recent data implicate locally produced steroids, termed neurosteroids, as regulators of neuronal function. Adrenal and gonadal steroidogenesis is controlled by changes in the steroidogenic acute regulatory protein (StAR); however, little is known about the regulation of ...

In the sheep there is a rapid increase in fetal adrenal growth and steroidogenesis during the last 10-15 days gestation (term = 147+/-3 days gestation). In the rat, peptides derived from the N-terminal region of POMC play a role in compensatory adrenal growth and in potentiation of ACTH-induced steroidogenesis. We therefore investigated the effects of infusion of bovine N-POMC-(1-77) and its biosynthetic derivative, N-POMC-(1-49) on adrenal growth and on the expression of adrenal steroidogenic enzymes in the late gestation sheep fetus. Twenty-seven pregnant ewes were used in this study. Fetal vascular catheters were inserted between 116-125 days gestation, and purified bovine N-POMC-(1-77) (2 microg/ml/h), N-POMC-(1-49) (2 microg/ml/h) and saline were each infused for 48 h between 136 and 138 days gestation. Intrafetal infusion of N-POMC-(1-77) resulted in an increased adrenal/fetal body weight ratio (94.6+/-5.7 mg/kg) compared with that in saline-infused (75.6+/-1.8 mg/kg), but not N-POMC-(1-49)-infused (82.7+/-6.1 mg/kg), fetal sheep. The ratio of CYP17 messenger RNA (mRNA) to 18S ribosomal RNA was also significantly higher in fetal adrenals ofthe N-POMC-(1-77)-infused group (49.1+/-4.7) compared with that in either the N-POMC-(1-49)-infused (20.4+/-6.4) or saline-infused (15.2+/-4.4) group. There was no difference, however, in the ratios of adrenal CYP11A1 mRNA/3beta-hydroxysteroid dehydrogenase/delta5,delta4-isomerase mRNA and CYP21A1 mRNA/18S ribosomal RNA among the N-POMC-(1-77)-, N-POMC-(1-49)-, and saline-infused groups. There was also no significant change in either plasma cortisol or ACTH concentrations in response to the infusion of either N-POMC-(1-77) or N-POMC-(1-49). In summary, intrafetal infusion of N-POMC-(1-77) stimulated fetal adrenal growth and resulted in a specific increase in adrenal CYP17 gene expression in late gestation. N-POMC-(1-77) may therefore play a modulatory role in the increase in fetal adrenal growth and steroidogenesis that occurs before birth.

The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. CYP17A1 and CYP19A1 proteins involved in steroidogenesis. Majority o polymorphisms have yet not been evaluated for their possible damaging effects on protein structure and function of both the genes. In present analysis, we tried to find out the effect of damage associated nsSNPs of both CYP17A1 and CYP19A1 gene by using various computational algorithms. Out of 205 and 246 nsSNPs reported for CYP17A1 and CYP19A1 gene, total 13 and 7 were predicted to affect the structure and function respectively. R125Q, R416H and F453S substitutions of CYP17A1 gene were not reported previously hence provide the new dataset of unexplored SNPs for their validation. By our results we also found that substitution of mainly Arginine or Phenyl alanine within conserved domain of redox binding, heam binging and redox partner site would cause partial or complete loss of function of both CYP17 and CYP19 gene.

This study examined the impact of a chronic physiological elevation of plasma cortisol levels on adrenal catecholamine synthetic enzyme and proenkephalin A mRNA expression in foetal sheep. Cortisol (2.5–3.0 mg.5 ml−1.24 h−1, n=9) or saline (0.9% saline, n=6) was infused into foetal sheep for 7 days between 109 days and 116 days gestation. Foetal plasma cortisol concentrations were higher (P<0.0005) in the cortisol infused foetuses when compared with the saline infused group (43.07±4.13 nmol.l−1 vs 1.67±0.10 nmol.l−1). There were no differences, however, in the plasma ACTH levels between the two groups. Using Northern blot analysis, adrenal phenylethanolamine N-methyltransferase (PNMT) mRNA expression was found to be reduced (P<0.005) fivefold in the cortisol infused foetuses when compared with the controls, as was the relative area of the adrenal medulla which stained positively with anti-PNMT (28.1±2.5% vs 44.8±4.8%, P<0.007). No effect of cortisol infusion was observed on adrenal tyrosine hydroxylase mRNA and protein expression or proenkephalin A mRNA expression. We conclude that before birth, adrenaline synthesis may be suppressed by a novel direct, or indirect, inhibitory effect of glucocorticoids on PNMT mRNA expression.

The public and scientific concern that chemicals present in the human diet and the environment and their ability to disrupt the normal hormonal milieu in humans and wildlife have become a high-profile international issue. In 1998, the Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) convened by the Environmental Protection Agency (EPA) recommended a tiered testing approach for the evaluation of estrogen, androgen, and thyroid-related effects of some 87,000 commercial chemicals and environmental contaminants. The function of this committee concluded with its final report, and the further implementation of the recommended testing strategy has now been carried forward with the assistance of the Endocrine Disruptor Methods Validation Subcommittee. The function of this body is to provide advice to the EPA on scientific and technical issues related specifically to the conduct of studies required for the validation of assays proposed by the EDSTAC as part of the tiered screening program. The EDSTAC recommended and alternative screening batteries encompass four in vitro mammalian assays. The current methodologies and validation status of the proposed in vitro EDSTAC assays are discussed and consist of estrogen/ androgen receptor binding, estrogen/androgen gene transactivation, and minced testis, and one alternate (placental aromatase) in vitro screening assay.

The objective of this work was to identify the reproductive toxico-pathological effects of cypermethrin (CY) in mature male rabbits. Apparently healthy adult age-and weight-matched rabbits (n = 40) were procured from the local market, kept under similar management conditions and divided into four equal groups. Different doses of CY (50, 100 and 150 mg kg À1 body mass) mixed in mustard oil were injected intraperitonealy at weekly intervals in male rabbits (groups B-D) prior to mating. Group A served as control and each animal in this group received equivalent volume of mustard oil. Treatment was continued for 71 days. Decreased testicular and epididymal sperm counts were recorded mostly in dose and time dependent manner in CY-treated rabbits. The serum testosterone concentrations in CY-treated rabbits were significantly lower than those of control group. Degeneration, arrested spermatogenesis and connective tissue (CT) proliferation in testes, while sperm-less seminal plasma and tailless spermatozoa in epididymis of CY-treated rabbits were observed. It was inferred that CY-induced defects in sperms and pathological alterations in testes and epididymis.

This paper describes the discovery of 17cq20g-dihydroxy-4-pregnen-3-one 20-sulphate (17,20g-P-sulphate) in urine of male and female plaice Pleuronectes platessa, in female Atlantic salmon Salmo salar and in female Dover sole Solea solea. 17a,20g-dihydroxy-4pregnen-3-one (17,2Og-P) induces oocyte final maturation in teleosts and, whereas levels of the free steroid in maturing/ovulating female plaice are generally <l ng ml-' and poorly associated with the stage of maturation, the levels of 17,20g-P-sulphate are around 1500 ng ml-' urine, 11 ng ml-' blood plasma and six-fold higher in maturing than in nonmaturing fish. There are also high levels in spermiating male plaice (ca. 2300 ng ml-' urine and 20 ng ml-' blood plasma). 17,20g-P-sulphate cannot be hydrolysed by snail (Helix pomatia) sulphatase, but can be completely solvolysed by treatment with tritluoroacetic acid (TFA)/ ethyl acetate (l/100, v/v) at 45" for 18 hr. A number of other sulphated steroids have been identified in plaice urine: cortisol, 11-deoxycortisol and 3a,l7a,2l-trihydroxy-5g-pregnan-20-one (which can all be hydrolysed by snail juice); 17a,20a-dihydroxy-4-pregnen-3-one and 17a,20g,2l-trihydroxy-4-pregnen-3-one (which can both be solvolysed by TFA/ethyl acetate).

Recent data implicate locally produced steroids, termed neuro- steroids, as regulators of neuronal function. Adrenal and go- nadal steroidogenesis is controlled by changes in the steroido- genic acute regulatory protein (StAR); however, little is known about the regulation of neurosteroid production. We now dem- onstrate unequivocally that StAR mRNA and protein are ex- pressed within glia and neurons in discrete

In the sheep fetus, adrenocortical growth and increases in steroidogenesis are essential for the maturation of a range of organ systems including the lungs, gut and brain, vital to successful adaptation to extra uterine life; for the appropriate hormonal responses to acute and chronic stress in utero and for the timing and process of parturition.  The precise mechanisms that coordinate growth and functional development of the ovine fetal adrenal gland during the last two weeks of gestation (term≈150 days of gestation) are unknown.  This thesis examines the relative roles of pituitary hormones, glucocorticoids, tissue growth factors and fetal stress, in modulating the increase in adrenocortical growth and steroid synthesis in late gestation.  Chapter 1 reviews the literature regarding adrenal growth and the synthesis of steroid hormones within the adrenal gland of the sheep fetus.  The relative roles of the fetal pituitary gland and cortisol in modulating the growth and functional activation of the adrenal cortex are also reviewed.  The potential role of peptides arising from the amino (N) terminal region of the adrenocorticotrophin (ACTH) precursor, pro opiomelanocortin (POMC), is specifically discussed.  Finally, the role of the insulin like growth factors (IGFs) and fetal stress are each considered in the regulation of the growth and functional development of the ovine fetal adrenal gland prior to birth.
Chapter 2 examines the changes in adrenal growth throughout gestation, and the messenger ribonucleic acid (mRNA) abundance of the adrenal steroid synthesising enzymes during the two weeks prior to birth in the fetal sheep.  The input of the hypothalamus in the regulation of fetal adrenal growth and function is also studied, by surgical disconnection of the fetal hypothalamus and pituitary (hypothalamo-pituitary disconnection; HPD) at approximately 110 days (d) of gestation.  Maintenance of fetal cortisol from 135 140 d of gestation, following fetal HPD, is also included to compare the separate effects of HPD and cortisol on adrenal development in late gestation.  This study demonstrates that there is a differential temporal regulation of mRNA expression of the steroid synthesising enzymes within the fetal adrenal during the two weeks prior to delivery.  While there is no change in the adrenal mRNA abundance of IGF II during the two weeks prior to delivery, the adrenal expression of mRNA for IGF binding protein 2 (IGFBP 2), the major fetal IGF II binding protein, decreases during late gestation, suggesting that bioactivity of the IGF axis may be modulated through altered abundance and activity of the IGF binding proteins during this time.  Fetal HPD at 110 d of gestation abolishes the late gestation increase in adrenal growth and steroidogenic enzyme mRNA abundance.  Replacement of cortisol following fetal HPD, however, stimulates adrenal growth in the absence of any effects on adrenal levels of IGF II or steroidogenic enzyme mRNA.  Cortisol may, therefore, act directly at the fetal adrenal to modulate the activity of locally produced growth factors, in part through altered abundance of the IGF binding proteins, or indirectly at the surgically disconnected pituitary to stimulate adrenal growth.
Chapter 3 examines the effects of a premature elevation of fetal plasma cortisol levels on adrenal growth and steroidogenesis in fetuses with an intact hypothalamo-pituitary-adrenal (HPA) axis, prior to the onset of the ontogenic rise in fetal circulating levels of adrenocorticotrophin (ACTH) and endogenous cortisol.  While exposure to elevated fetal circulating levels of cortisol during the period 109 116 d of gestation does not stimulate adrenal growth or steroidogenic enzyme gene expression, the adrenal expression of mRNA for IGFBP 2 and the steroid metabolising enzyme 11β hydroxysteroid dehydrogenase (11βHSD 2) is decreased.  It is possible that a decrease in adrenal IGFBP 2 and 11βHSD 2 expression and increased intra adrenal glucocorticoids may enhance adrenal growth and steroidogenic responsiveness only when the fetal adrenal is simultaneously exposed to the high ACTH concentrations which prevail in the week before birth, or during chronic intra uterine stress.
Studies in the fetal sheep have demonstrated that pro ACTH and N terminal POMC(1 77) are present in 20 50 fold higher concentrations than is ACTH(1 39) in fetal sheep circulation.  While the N POMC peptides have potent mitogenic and steroidogenic effects on adult rat adrenocortical cells in vivo and in vitro, no studies have examined their effect on fetal adrenal development in utero.  Chapter 4 examines the role of peptides derived from the N terminal region of POMC in the regulation of fetal adrenal growth and development.  N POMC(1 77) and N POMC(1 49) were extracted and purified from adult bovine pituitaries and infused into the circulation of fetal sheep during late gestation.  Intra fetal infusion of N POMC(1 77), but not N POMC(1 49), results in an increase in adrenal weight and in the expression of mRNA for the adrenal steroid synthesising enzyme P450c17 (CYP17).  These data indicate a possible novel role for the N terminal POMC peptide in adrenal growth and steroidogenesis before birth.
IGFs are potent mitogenic factors and are important in the regulation of many aspects of fetal growth.  Previous studies have demonstrated the presence of IGF I and IGF II mRNA and peptide and IGF receptors in the adrenal glands of the developing fetus.  Thus, IGFs potentially play an important role in the growth and development of the fetal adrenal.  In Chapter 5, the effect of intra fetal infusion of IGF I on adrenal maturation has been investigated.  Consistent with in vitro studies, a 10 d intra fetal infusion of recombinant human IGF I results in a marked increase in adrenal growth, in the absence of an effect on the expression of mRNA for the steroidogenic enzymes.  These results demonstrate for the first time that IGF I has a substantial growth promoting effect on the adrenal gland of the ovine fetus in vivo.
Finally, in Chapter 6, the response of the fetal adrenal gland to chronic fetal growth restriction has been examined in an experimental model wherein restriction of placental growth is secondary to the surgical removal of most of the sites of placental development (the maternal caruncles) prior to mating.  A quantitative relationship has been demonstrated between adrenal growth and the degree of fetal growth restriction, regardless of the cause of growth restriction.  Thus, there is a continuum among fetuses in which growth restriction is induced experimentally by carunclectomy and in fetuses where growth restriction occurs spontaneously, i.e. those control singleton and twin fetuses which were <3.5 kg.  Placentally restricted fetal sheep have a higher ratio of adrenal : fetal body weight, and an enhanced adrenal expression of mRNA for the steroid synthesising enzyme P450scc (CYP11A1), the rate limiting enzyme in steroid synthesis, in addition to higher fetal circulating levels of cortisol.  While adrenal growth is promoted in the placentally restricted group, the adrenal expression of mRNA for IGF II is suppressed, in the absence of any changes in IGFBP 2 mRNA expression.
In conclusion, this dissertation describes the interactions among pituitary derived peptides, intra adrenal exposure to glucocorticoids and the local adrenal and endocrine IGF axes in the growth and functional activation of the ovine fetal adrenal gland before birth.  The involvement of these systems in the fetal response to chronic stress and intra uterine growth restriction is also considered.  Throughout this thesis, several conceptual models of the control of adrenal growth and function in late gestation are proposed and developed.

We have investigated the effect of intrafetal cortisol administration , before the normal prepartum cortisol surge, on the expression of 11 hydroxysteroid dehydrogenase (11HSD) type 2 mRNA in the fetal adrenal. We also determined whether increased fetal cortisol concentrations can stimulate growth of the fetal adrenal gland or increase expression of adrenal ste-roidogenic enzymes. Cortisol (hydrocortisone succinate: 2.0–3.0 mg in 4.4 ml/24 h) was infused into fetal sheep between 109 and 116 days of gestation (cortisol infused; n 12), and saline was administered to control fetuses (saline infused; n 13) at the same age. There was no effect of cortisol infusion on the fetal adrenal:body weight ratio (cortisol: 101.7 5.3 mg/kg; saline: 108.2 4.3 mg/kg). The ratio of adrenal 11HSD-2 mRNA to 18S rRNA expression was significantly lower, however, in the cortisol-infused group (0.75 0.02) compared with the group receiving saline (1.65 0.14). There was no significant effect of intrafetal cortisol on the relative abundance of adrenal CYP11A1, CYP17, CYP21A1, and 3HSD mRNA. A premature elevation in fetal cortisol therefore resulted in a suppression of adrenal 11HSD-2. Increased intra-adrenal exposure to cortisol at this stage of gestation is, however, not sufficient to promote adrenal growth or steroidogenic enzyme gene expression.

1. We have investigated the role of the fetal hypothalamo-pituitary axis in the control of adrenocortical growth and steroidogenesis in the sheep fetus during late gestation. Plasma concentrations of ACTH(1-39) increased between 120-125 and 136-142 days (P &lt; 0.05), but did not change after surgical disconnection of the fetal hypothalamus and pituitary (HPD) at 106-120 days gestation. There was no effect of either gestational age or HPD on the circulating concentrations of the ACTH-containing precursors pro-opiomelanocortin (POMC) and pro-ACTH (the 22 kDa N-terminal portion of POMC). 2. In the fetal sheep adrenal, the relative abundance of the mRNAs of the steroidogenic enzymes CYPIIA1 and CYP21A1 increased between 130-135 and 136-140 days gestation (P &lt; 0.05) and remained high after 141 days, whereas that of CYP17 mRNA increased after 141 days gestation (P &lt; 0.05). The abundance of adrenal 3 beta-HSD mRNA did not change between 130 and 145 days. 3. Hypothalamo-pituitary dis...

In the sheep, there is a rapid increase in fetal adrenal growth and steroidogenesis during the last 10–15 days gestation. Recently, we have shown that infusion of POMC 1–77 increases fetal adrenal growth but does not significantly alter fetal plasma cortisol concentrations. Phosphorylation and inactivation of the pRB protein, which is required for progression into the DNA synthetic phase of the cell-cycle is conducted by a holoenzyme, for which cyclin D1 gene encodes the rate-limiting regulatory subunit. To further elucidate the mechanisms by which POMC 1–77 regulates adrenal growth, we therefore examined adrenal expression of the rate-limiting cell cycle protein, cyclin D1, from fetuses infused for 48 hr with POMC 1–77 (n=6), POMC 1–49 or Saline (n=6). There was no significant difference in the adrenal expression of cyclin D1 mRNA levels between POMC 1–77, 1–49 and saline infused fetuses. There was no significant correlation between cyclin D1 (4.0 Kb) and adrenal weight. In summary, these data do not demonstrate that the rate-limiting cell cycle protein, cyclin D1, is activated to stimulate adrenal growth following infusion of POMC 1–77 in the fetal sheep in late gestation.

In the sheep, there is a rapid increase in fetal adrenal growth and steroidogenesis during the last 10-15 days gestation. Recently, we have shown that infusion of POMC (1-77) increases fetal adrenal growth and expression of CYP17 mRNA but does not significantly alter fetal plasma cortisol concentrations [1]. We therefore investigated the effects of infusion of bovine POMC (1-77) and its biosynthetic derivative POMC (1-49) on adrenal StAR mRNA expression. At 136d gestation, POMC (1-77) (n=5 fetuses; 2microg/ml/h), POMC (1-49) (n=5 fetuses, 2microg/ml/h) or Saline (n=5 fetuses, 1ml/h) was infused for 48h. At 138d, fetal adrenal glands were collected and frozen in liquid N2 until RNA was extracted. Northern blot analyses demonstrated a major transcript for StAR mRNA at 3.0kb in fetal adrenal glands from all treatments. The membrane was stripped and re-probed with a P-labelled rat 18S rRNA oligo-probe to verify equal RNA loading. Infusion of POMC (1-77), but not POMC (1-49), resulted in a suppression of fetal adrenal StAR mRNA:18S rRNA when compared to adrenal StAR mRNA:18S rRNA from saline-infused controls. Our data suggest POMC (1-77) may act via separate mechanisms to increase fetal adrenal growth and to limit adrenal steroidogenesis through suppression of StAR mRNA.

Recent data implicate locally produced steroids, termed neurosteroids,
as regulators of neuronal function. Adrenal and gonadal
steroidogenesis is controlled by changes in the steroidogenic
acute regulatory protein (StAR); however, little is known
about the regulation of neurosteroid production. We now demonstrate
unequivocally that StAR mRNA and protein are expressed
within glia and neurons in discrete regions of the
mouse brain, and that glial StAR expression is inducible. Consistent
with a role in de novo neurosteroidogenesis, StAR colocalizes
with the cholesterol side-chain cleavage enzyme
P450scc in both mouse and human brains. These data support
a role for StAR in the production of neurosteroids and identify
potential sites of active de novo steroid synthesis in the brain.