title: C cells evolve at the same rhythm as follicular cells when thyroidal status changes in rats.
abstract: C cells are primarily known for producing calcitonin, a hypocalcemic and hypophosphatemic hormone. Nevertheless, besides their role in calcium homeostasis, C cells may be involved in the intrathyroidal regulation of follicular cells, suggesting a possible interrelationship between the two endocrine populations. If this premise is true, massive changes induced by different agents in the activity of follicular cells may also affect calcitonin-producing cells. To investigate the behaviour of C cells in those circumstances, we have experimentally induced two opposite functional thyroid states. We hyperstimulated the follicular cells using a goitrogen (propylthiouracil), and we suppressed thyroid hormone synthesis by oral administration of thyroxine. In both scenarios, we measured T(4), TSH, calcitonin, and calcium serum levels. We also completely sectioned the thyroid gland, specifically immunostained the C cells, and rigorously quantified this endocrine population. In hypothyroid rats, not only follicular cells but also C cells displayed hyperplastic and hypertrophic changes as well as increased calcitonin levels. When exogenous thyroxine was administered to the rats, the opposite effect was noted as a decrease in the number and size of C cells, as well as decreased calcitonin levels. Additionally, we noted that the two cell types maintain the same numerical relation (10 +/- 2.5 follicular cells per C cell), independent of the functional activity of the thyroid gland. Considering that TSH serum levels are increased in hypothyroid rats and decreased in thyroxine-treated rats, we discuss the potential involvement of thyrotropin in the observed results.
authors.affiliation: Department of Normal and Pathological Cytology and Histology, School of Medicine, University of Seville, Av. Sánchez Pizjuán S/N, Seville, Spain. ilacave@us.es
authors.forename: Inés
authors.initials: I
authors.lastname: Martín-Lacave
authors.forename: María J
authors.initials: MJ
authors.lastname: Borrero
authors.forename: José C
authors.initials: JC
authors.lastname: Utrilla
authors.forename: José M
authors.initials: JM
authors.lastname: Fernández-Santos
authors.forename: Manuel
authors.initials: M
authors.lastname: de Miguel
authors.forename: Jesús
authors.initials: J
authors.lastname: Morillo
authors.forename: Juan M
authors.initials: JM
authors.lastname: Guerrero
authors.forename: Rocío
authors.initials: R
authors.lastname: García-Marín
authors.forename: Esperanza
authors.initials: E
authors.lastname: Conde
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002116:Calcitonin / Q000097:blood; D002118:Calcium / Q000097:blood; D048429:Cell Size / Q000187:drug effects; D006042:Goiter / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology*; D007037:Hypothyroidism / Q000097:blood / Q000139:chemically induced / Q000473:pathology*; D008297:Male; D019899:Paracrine Communication / Q000502:physiology; D011441:Propylthiouracil; D051381:Rats; D017208:Rats, Wistar; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D011441:Propylthiouracil; D013972:Thyrotropin; D002116:Calcitonin; D013974:Thyroxine; D002118:Calcium