Comparative effects of diverse vertebrate gonadotropins on estradiol-17 beta formation in vitro in an immature rat Sertoli cell bioassay.

The biopotencies of pituitary gonadotropins (GTHs) from various vertebrate classes were examined in an in vitro rat Sertoli cell bioassay which was previously established for mammalian follicle-stimulating hormones (FSHs). Potencies of the gonadotropins were determined by incubation of Sertoli cells obtained from 10-day-old rats, with increasing doses of GTHs, which resulted in dose-related and parallel estradiol-17 beta formation converted from added 19-hydroxy-androstenedione. In general, mammalian (human and ovine) FSHs were most potent, avian (chicken, turkey, and ostrich) FSHs were intermediate, and reptilian (snapping turtle) and amphibian (bullfrog) FSHs were the least potent.

Complete amino acid sequences of follitropin and lutropin in the ostrich, Struthio camelus.

We determined the complete amino acid sequences of two pituitary gonadotropins, follitropin and lutropin in the ostrich, thereby providing the first information on the structure of avian follitropin. Ostrich follitropin and lutropin both consist of two subunits: a common alpha-subunit and a hormone-specific beta-subunit. The alpha-subunit is composed of 96 amino acid residues and has 70-80% sequence identity with the alpha-subunits of most vertebrates.

The groove between the alpha- and beta-subunits of hormones with lutropin (LH) activity appears to contact the LH receptor, and its conformation is changed during hormone binding.

Gonadotropins are heterodimeric glycoprotein hormones that control vertebrate fertility through their actions on gonadal lutropin (luteinizing hormone, LH) and follitropin (follicle-stimulating hormone, FSH) receptors. The beta-subunits of these hormones control receptor binding specificity; however, the region of the beta-subunit that contacts the receptor has not been identified. By a process of elimination we show this contact to be the portions of beta-subunit loops one and three found in a hormone groove created by the juxtaposition of the alpha- and beta-subunits.

The complete amino acid sequence of growth hormone from sturgeon (Acipencer guldenstadti).

The complete amino acid sequence of growth hormone (GH) from a chondrostean species, the sturgeon (Acipencer gludenstaditi), has been determined. Two variants of GH, termed GH I and GH II, were isolated from the pituitary by alkaline extraction, gel filtration on a Sephadex G-100 column, and reversed-phase high-performance liquid chromatography (rpHPLC) on a TSK gel ODS-120T column. The purified proteins were confirmed to be GHs by immunoblotting using bovine and chum salmon GH antisera.

Comparison of lipolytic and antilipolytic activities of lower vertebrate growth hormones on chicken adipose tissue in vitro.

Mammalian and avian growth hormones (GH) (pituitary derived or biosynthetic) exert two effects on chicken adipose tissue explants in vitro. They (i) increase the basal rate of glycerol release a lipolytic effect) and (ii) inhibit glucagon-stimulated glycerol release (an antilipolytic effect). The ability of lower vertebrate GH preparations to exert lipolytic and antilipolytic effects was examined and biological activity was compared to differences in amino-acid residue sequences and to predicted structure.