Interactions among basic fibroblast growth factor, epidermal growth factor, insulin, and insulin-like growth factor-I (IGF-I) on cell numbers and steroidogenesis of bovine thecal cells: role of IGF-I receptors

• Published in: Biology of reproduction 1996-01, Vol.54 (1), p.255-263
• Main Authors: Spicer, L.J. (Oklahoma State University, Stillwater, OK.), Stewart, R.E
• Format: Article
• Language: English
• Subjects: ANDROSTENEDIONA; ANDROSTENEDIONE; Androstenedione - biosynthesis; Animals; Biological and medical sciences; BOVIN; Cattle; Cell Count; CELLULE; CELULAS; CRECIMIENTO; CROISSANCE; CULTIVO DE CELULAS; CULTURE DE CELLULE; Drug Interactions; Epidermal Growth Factor - pharmacology; Female; Fibroblast Growth Factor 2 - pharmacology; Fundamental and applied biological sciences. Psychology; GANADO BOVINO; Growth Substances - pharmacology; HORMONAS; HORMONE; Hormone metabolism and regulation; Insulin - pharmacology; Insulin-Like Growth Factor I - pharmacology; INSULINA; INSULINE; Mammalian female genital system; METABOLISME DES STEROIDES; METABOLISMO DE ESTEROIDES; PROGESTERONA; PROGESTERONE; Progesterone - biosynthesis; PROMOTEUR DE CROISSANCE ANIMALE; PROMOTORES DEL CRECIMIENTO ANIMAL; RECEPTEUR D'HORMONE; Receptor, IGF Type 1 - physiology; RECEPTORES DE HORMONAS; Steroids - biosynthesis; Theca Cells - cytology; Theca Cells - drug effects; Theca Cells - metabolism; Vertebrates: reproduction
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod54.1.255

The objectives of the present study were to determine the interaction among basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), insulin, and insulin-like growth factor-I (IGF-I) on cell numbers, steroidogenesis, and IGF-I binding sites in cultured thecal cells. Cells from large (greater than or equal to 8 mm) follicles were collected from cattle and cultured for 4 days. Treatment with 1-30 ng/ml of bFGF for 2 days increased (p 0.05) thecal cell numbers but inhibited (p 0.05) androstenedione and progesterone production in the presence of insulin alone or insulin plus LH. Treatment with 1-30 ng/ml of bFGF for 2 days also inhibited (p 0.05) the number of specific 125I-IGF-I binding sites in thecal cells, with maximal inhibition being detected at 1 ng/ml; coculture with 100 ng/ml LH did not influence this effect. In the absence of bFGF and the presence of LH, 30 ng/ml of IGF-I increased thecal cell numbers and production of androstenedione and progesterone. However, cotreatment with 10 ng/ml bFGF inhibited thecal cell response to IGF-I. Cotreatment consisting of 3-100 ng/ml EGF with insulin increased (p 0.05) thecal cell numbers but decreased (p 0.05) androstenedione end progesterone production and the number of specific 125I-IGF-I binding sites in thecal cells, with maximal inhibition observed at 3 ng/ml of EGF. Also, cotreatment consisting of 3 and 10 ng/ml of EGF with IGF-I plus LH inhibited (p 0.05) cell numbers and production of androstenedione and progesterone by thecal cells. These results suggest that bFGF, EGF, insulin, and IGF-I may interact to play a significant role in basal and LH-modulated thecal cell steroidogenesis and mitogenesis during follicular development in cattle