Gonadotropic hormone

Rimington and Rowlands165 have isolated an extremely active preparation from the serum of pregnant mares. This material was obtained in a high degree of purity and was shown to contain hexose and hexosamine in the molar ratio of 2/1. In the fractionation it appeared that, at first, the hexose content decreases as the potency is raised, but later this trend is reversed. It was shown that hexose content could not be taken as indication of gonadotropic activity. The hexose/hexosamine ratio was 2/1 as in normal serum mucoproteins, so that this gonadotropic hormone may be a modified serum mucoprotein. 

To stimulate spermatogenesis both testosterone and gonadotropic hormones need to be administered. 

In the gregarious phase of Schistocerca gregaria, final ecdysis allows differentiation of gland cells involved, under exclusive gonadotropic hormone... 

Q2 Explain the profile of gonadotropic hormones activity, i.e. luteinizing hormone (LH) and follicle-stimulating hormone (FSH), in a typical 28-day female reproductive cycle... 

The most common secretory neoplasm of the anterior pituitary gland is a prolactin-secreting adenoma (prolactinoma). An early symptom of prolactin excess is a milky discharge from the breasts. Because hyperprolactinemia may suppress the secretion of gonadotropic hormones (e.g., LH, FSH), menstrual irregularity, amenorrhea, and infertility may occur in women. In men, gonadotropic hormone dysfunction may lead to reduced libido, sexual impotence, and infertility. 

One of the major problems encountered by workers in the field of the gonadotropic hormones has been that of obtaining FSH preparations free from LH activity and LH preparations free from FSH. Accordingly, most of the work so far reported in the literature has been concerned with mixtures of these hormones. Even now after 40 years of active research, it remains a matter of considerable difficulty to provide a precise definition of the gonadotropins in terms of their biological activity. 

Since the identities of the gonadotropic hormones remain uncertain, it is important before discussing assay procedures, to examine in some detail the various techniques for their preparation. Such methods may of themselves lead to differences in the composition or structure of the final products of extraction as well as to variations in the type of protein contaminants remaining in the purified hormone preparation. Since immunological procedures hinge on the availability of pure FSH and LH, it is likely that the results of such assays will vary depending on the methods by which these purified hormones have been obtained. 

There are two basic methods for extracting gonadotropic hormones from pituitary glands (1) extraction into organic salt solutions and (2) extraction with aqueous salt solutions. 

The tables indicate that there is still considerable divergence of opinion regarding both the properties and chemical composition of the gonadotropic hormones. Indeed, in some reports the amino acid analyses of two LH preparations have been found to be more dissimilar than those for FSH and LH. It should especially be noted that Butt (Bll) and Stoekell Hartree (S27) analyzed the same preparation of LH and arrived at very different results with respect to amino acid content this finding sug-... 

This variation in antibody specificity with successive inoculations of an animal has proved a matter of considerable diflBculty in the field of the radioimmunoassay of the gonadotropic hormones. The work of Odell et al. (03) demonstrates that, during the production of their antisera to human FSH, their experience was similar to that of Benjamini et al. (B4), namely, that early in immunization the population of antibodies which reacted with both FSH and LH was 100 times... 

In the present state of our knowledge concerning the chemistry of gonadotropic hormones, the raising of antisera suitable for immunoassay is a matter of chance and has rarely been achieved. Until more is known regarding the immunodominant structures of FSH and LH, two points merit emphasis with a view to maintaining a supply of specific antisera. The first is that different individuals produce antisera with different specificities, and this specificity is under genetic control (see Section... 

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