The Use of Non-Castrate Parabiotic Rats for the Evaluation of Plasma Gonadotrophins

Johnson, Donald C.

doi:10.1530/acta.0.0510269

Cited by 11 publications

(8 citation statements)

References 4 publications

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“…The detection of gonadotropins in the serum of prepubertal children is consistent with the presence of gonadotropic activity in the urine [20,32,44] and in the pituitary glands of children [3,47,56] and of immature animals [28,29,31]. This finding, and the changes in gonadotropin secretion during puberty described in this report, does not shed light on the mechanism responsible for the initiation of puberty.…”

supporting

confidence: 81%

Hormonal Changes in Puberty II. Correlation of Serum Luteinizing Hormone and Follicle Stimulating Hormone With Stages of Puberty and Bone Age in Normal Girls

et al. 1970

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The concentration of serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) was determined using a double antibody radioimmunoassay in 129 normal girls. Of this group, 48 were prepubertal (PjJ and 81 girls were at varying stages of pubertal development from P 2 to P 5 . The mean serum LH concentration was similar in the prepubertal (Pj) and nonmenstruating girls (P2-4) (3.8-4.2 ng/ml) (table I, fig. 1). A difference was observed in the serum FSH levels that increased steadily from 1.70 ng/ml at P x to 3.4 ng/ml at stage P 3 of puberty. No further change in the concentration of serum FSH was seen in girls from P s to P 4 . The LH/FSH ratio was lower in girls at stage P 2 than in the prepubertal girls.In the menstruating girls (P 6 ), mean concentration of serum LH was within the same range (5.1-4.6 ng/ml) during the three phases of the menstrual cycle. Changes in the concentration of serum FSH was observed in menstruating girls: phase I (days 1-12), 3.99 ng/ml; phase II (days 13-18), 3.59 ng/ml; and phase III (days 19-30), 2.51 ng/ml.The relation of the serum LH and FSH levels and LH/FSH ratio to chronologic age was studied (table III). The concentration of LH was not significantly different in girls of 8-12 years. Serum FSH increased from 9 to 13 years. The LH/FSH ratio decreased at 9 years of age with no further change from 10 to 15 years. In addition, serum LH and FSH levels and LH/FSH ratio were compared with bone age (table IV). Serum LH was slightly but significantly less in girls with a bone age of 8 years than in those with a bone age of 6 years. A significant increase in FSH and LH levels was observed in girls with a bone age of 12 years compared with those with a bone age of 8 years.In 14 children with multiple pituitary hormone deficiencies, the serum LH concentration was 2.2 ng/ml and the serum FSH concentration was 1.5 ng/ml. In 12 patients with XO gonadal dysgenesis of pubertal age, the mean concentration of serum LH was 11.2 ng/ml and mean concentration of serum FSH was 54.5 ng/ml. In two patients with XO gonadal dysgenesis, aged 6.5 and 9 years, the serum LH values were 2-5 and 4.5 ng/ml, and the serum FSH values were 1.5 and 2.75 ng/ml, respectively.The serum values described are of relative not absolute significance. Although the results indicate that small amounts of gonadotropins are secreted prior to the onset of signs of puberty, it is important to emphasize the necessity of better defining the lower limits of sensitivity of the assays for serum samples. SIZONENKO, BURR, KAPLAN and GRUMBACH 37The detection of serum FSH and LH in prepubertal children suggests that the hypothalamic-pituitary gonadal axis is at a low level of activity and already operative at this stage of development. The precise time of initiation of cyclical secretion of LH and FSH (the FSH and LH ovulatory surge) in pubertal girls and its relation to maturational changes in the ovary is not known but it seems likely that the increase in estrogen secretion by the ovary as puberty advances acts as a positive fe...

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supporting

confidence: 81%

Hormonal Changes in Puberty II. Correlation of Serum Luteinizing Hormone and Follicle Stimulating Hormone With Stages of Puberty and Bone Age in Normal Girls

et al. 1970

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“…It is therefore likely that this testicular growth reflects an increased fsh secretion (Greep, 1961) with a minimal lh output. In fact, the presence of circulating fsh has been demon¬ strated in experiments with parabionts during this period (Johnson, 1966). It is tempting to postulate that the testes of prepuberal rats are sequentially exposed to the action of fsh, and then to lh (and perhaps continued secretion of fsh) resulting in the spermatid formation in the tubules by 44 to 45 days of life, the implication being that fsh is involved in the early stages of spermatogenesis, while its further progression depends upon synergism of fsh with lh or androgens.…”

Section: Discussionmentioning

confidence: 94%

Age-Dependent Changes in Pituitarygonadal Relationships

Labhsetwar¹

1970

Reproduction

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Summary. Pituitary levels of fsh (Steelman-Pohley assay) and lh (Parlow assay) were determined in male rats of various ages. The lh level began to rise by Day 33 of life, reached a peak between Days 43 and 47, and declined in the post-puberal period.The fsh level (\g=m\g/mg and \g=m\g/pituitary/100g body weight) began to rise very much earlier and had already reached its peak around Day 33, when testicular growth was rapid but before full spermatogenesis was established. In post-puberal rats, the fsh levels were much lower than those reached before puberty.The implication of these findings and the possibility that fsh and lh are sequentially involved in initiating spermatogenesis in the puberal rat are discussed.

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“…Such a relationship has been demonstrated in animals. Plasma from prepubertal rats contains LH that is detectable by its effects on a parabiont hypophysectomized partner (27). When immature rats are joined in parabiosis and one partner is castrated, the other undergoes precocious sexual development (28).…”

Section: Methodsmentioning

confidence: 99%

Radioimmunoassay for Luteinizing Hormone in Human plasma Or Serum: Physiological Studies*

Odell¹,

Ross²,

Rayford³

1967

J. Clin. Invest.

501

104

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Summary. It is not practical to quantitate gonadotropin in the blood of normal men and women by utilizing bioassays. We have developed a method for sensitive, precise, and specific radioimmunoassay of luteinizing hormone (LH) in human serum or plasma. Antisera were developed against human chorionic gonadotropin, and one of these was selected for extensive cross-reaction with human LH. Highly purified LH was radioiodinated by the method of Greenwood, Hunter, and Glover. Separation of antibody-bound from free LH-131I was accomplished by a double antibody technique. Dose-response curves for the purified LH, an impure urinary LH preparation, pituitary powder, and LH in plasma were all identical. Immunoassay and bioassay of impure urinary and pituitary gonadotropin preparations in terms of a common standard resulted in an index of discrimination of close to unity. LH levels in plasma from 32 adult men and 30 women outside the midcycle ranged from 0.6 to 3.2 mfAg per ml (1 m/Ag of our laboratory LH standard is equivalent to 8 mU of the Second International Reference Preparation of Human Menopausal Gonadotropin). Levels were remarkably constant in men from day to day and in women except at midcycle, when a sharp peak occurred lasting less than 24 hours. In all women studied who had a midcycle LH peak, mean plasma LH levels during the follicular phase of the menstrual cycle were higher than mean values obtained during the luteal phase. Prepubertal children had detectable plasma LH, and mean values were only slightly less than in adults. Plasma from castrate men or women or postmenopausal women contained 4.5 to 10.5 mug per ml. Clomiphene treatment of four men resulted in a doubling of plasma LH in 5 days. Introduction Wide, Roos, and Gemzell (1), using an immunoassay based on hemagglutination inhibition, first reported that human luteinizing hormone (HLH) cross-reacts with human chorionic gonadotropin (HCG) for binding to antibodies directed against HCG. In 1964 Paul and Odell (2) first developed a radioimmunoassay for HCG.

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The Use of Non-Castrate Parabiotic Rats for the Evaluation of Plasma Gonadotrophins

Cited by 11 publications

References 4 publications

Hormonal Changes in Puberty II. Correlation of Serum Luteinizing Hormone and Follicle Stimulating Hormone With Stages of Puberty and Bone Age in Normal Girls

Hormonal Changes in Puberty II. Correlation of Serum Luteinizing Hormone and Follicle Stimulating Hormone With Stages of Puberty and Bone Age in Normal Girls

Age-Dependent Changes in Pituitarygonadal Relationships

Radioimmunoassay for Luteinizing Hormone in Human plasma Or Serum: Physiological Studies*

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