Regulation of secretion of pituitary gonadotropins in human embryogenesis

Levina, S. E.

doi:10.1007/bf01125595

Cited by 3 publications

(3 citation statements)

References 6 publications

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“…Similar to our findings these authors reported higher plasma FSH levels in girls 0-2 yr than in boys. This sex difference in FSH levels seems to be a constant finding both in the human during fetal life (11,(18)(19)(20), at birth (10), and during infancy (12), and in primates (21). The origin of testosterone has not been clearly identified in infants of either sex.…”

Section: Discussionmentioning

confidence: 99%

Hypophyso-Gonadal Function in Humans during the First Year of Life

Forest¹,

Sizonenko²,

Cathiard³

et al. 1974

J. Clin. Invest.

402

170

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A B S T R A C T Total and unbound testosterone and A4-androstenedione have been determined in 104 cord blood samples. The same sexual steroids and pituitary gonadotropins have been measured in 46 normal male infants aged 27-348 days and 34 normal female infants aged 19-332 days.In cord blood of female neonates mean total and unbound testosterone was 29.6±7.5 and 0.89±0.4 ng/100 ml, respectively (mean±l SD); A4-androstenedione was 93±38 ng/100 ml. In male neonates mean plasma total and unbound testosterone was 38.9±10.8 and 1.12±0.4 ng/100 ml; A'-androstenedione was 85±27 ng/100 ml.In female infants testosterone concentrations remained constant during the lst yr of life with a mean concentration of 7±3 ng/100 ml. Mean unbound testosterone and A'-androstenedione concentrations were 0.05±0.03 and 16.7±8.3 ng/100 ml, respectively. Mean plasma levels of follicle-stimulating hormone and luteinizing hormone were 8.7±3.3 and 12.9±7.7 mU/ml.In male infants mean plasma total testosterone concentration increased to 208±68 ng/100 ml from birth to 1-3 mo of age, decreasing thereafter to 95±53 ng/100 ml at 3-5 mo, 23.2±18 ng/100 ml at 5-7 mo, and reached prepubertal levels (6.6±4.6 ng/100 ml) at 7-12 mo.Mean unbound testosterone concentration plateaued from birth to 1-3 mo of age (1.3±0.2 ng/100 ml) decreasing to prepubertal values very rapidly. Mean A4-androstene-

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Section: Discussionmentioning

confidence: 99%

Hypophyso-Gonadal Function in Humans during the First Year of Life

Forest¹,

Sizonenko²,

Cathiard³

et al. 1974

J. Clin. Invest.

402

170

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“…According to Levina (1970) and Gilmore & Dobbie (1975), LHRH activity in the human fetal hypothalamus cannot be detected before the sixteenth week. Siler-Khodr et al (1974) have shown that pituitaries obtained from anencephalic fetuses produce reduced amounts of gonadotrophins as compared with normal fetuses, which illustrates the role of the hypothalamus in fetal pituitary function.…”

Section: (C) Hypothalamic Control Of Gonadal Function In the Fetusmentioning

confidence: 99%

Hypothalamic‐pituitary‐gonadal Relationships in Man From Birth to Puberty

Forest

Peretti

Bertrand

1976

Clinical Endocrinology

134

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Gonadal function depends upon activities at various levels. Thus there is: (a) a central level (extra-hypothalamic, hypothalamic, and anterior pituitary); (b) an intermediate level (gonadal and plasma), and (c) a peripheral level consisting of the target organs to which the hormonal message is directed. These determine both the expression of gonadal function (physical, physiological, or psychological) and the feedback regulation of the secretion of gonadotrophins.(a) Central level (i) Extra-hypothalamic centres. The production of LH releasing hormone (LHRH) is affected in the rat, and probably in primates as well, by extra-hypothalamic stimuli coming, in particular, from the amygdala and the hippocampus. Adrenergic regulation exists at this level, noradrenaline having a stimulatory and dopamine an inhibitory effect (Bliss et al., 1972).(ii) Hypothalamic centres. These are localized in particular in the pre-optic area. Immunochemical techniques have demonstrated that LHRH is secreted by neurones of the arcuate nucleus, and released into the capillary plexus proximal to the hypophyseal portal system at the level of the median eminence, thereby reaching the anterior pituitary (Barry & Dubois, 1974;Setalo et al., 1975).(iii) Gonadotrophin secreting cells of the anterior pituitary. These synthesize and secrete the gonadotrophins, LH and FSH, under the influence of LHRH (Schally et al., 1972). The pituitary gonadotrophins stimulate the synthesis and the secretion of the gonadal

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“…Until the third month of gestation, only a-subunits ofLH and FSH are found in the pituitary gland (Bugnon et al, 1977;Dubois et al, 1978). Biological activity of these subunits is found at the same period of gestation (Levina, 1970;Parlow, 1974). Furthermore, tissue culture of 10-20-week-old fetal pituitary cells was shown to result in a release of gonadotrophins that could be modulated by the addition of either GnRH or estradiol to the medium (Gitlin and Biasucci, 1969a;Gailaini et al, 1970;Groom et al, 1971;Silver et al, 1972;Groom and Boyns, 1973).…”

Section: Gonadotrophins During Fetal Lifementioning

confidence: 99%

Human Growth

1986

107

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Regulation of secretion of pituitary gonadotropins in human embryogenesis

Cited by 3 publications

References 6 publications

Hypophyso-Gonadal Function in Humans during the First Year of Life

Hypophyso-Gonadal Function in Humans during the First Year of Life

Hypothalamic‐pituitary‐gonadal Relationships in Man From Birth to Puberty

Human Growth

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