Immunoreactive prolactin forms colocalize with vasopressin in neurons of the hypothalamic paraventricular and supraoptic nuclei.
The prolactin (PRL) gene is expressed in the hypothalamo-neurohypophyseal system as revealed by the detection of the PRL mRNA and of PRL-like immunoreactive and biologically active proteins in hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei and in the neurohypophysis. We have investigated the distribution of cells containing PRL-like molecules in the PVN and SON by immunocytochemistry with a specific antiserum directed against the 16-kD N-terminal fragment of PRL. PRL-positive cells were found to be concentrated throughout the ventral SON and in the lateroposterior region of the PVN. The cellular distribution of PRL-immunoreactive cells resembled more closely that of vasopressin (VP) than that of oxytocin magnocellular neurons. Moreover, double immunofluorescence labelling, followed by confocal microscopy, indicated the coexistence of PRL- and VP-related antigens within the same neurons of the PVN and SON. Pre-embedding immunoperoxidase on the ultrastructural level showed a PRL-like product in granular-type particles within the neural soma and projections in the SON and PVN. These findings are consistent with the expression and secretion of PRL-like molecules by vasopressinergic neurons of the hypothalamo-neurohypophyseal system.
Mejía
S
S
Centro de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, México.
Morales
M A
MA
Zetina
M E
ME
Martínez de la Escalera
G
G
Clapp
C
C
D000818:Animals; D005260:Female; D007150:Immunohistochemistry; D009474:Neurons / Q000737:chemistry*; D010121:Oxytocin / Q000032:analysis*; D010286:Paraventricular Hypothalamic Nucleus / Q000737:chemistry* / Q000166:cytology; D011388:Prolactin / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D013347:Subcellular Fractions / Q000737:chemistry; D013495:Supraoptic Nucleus / Q000737:chemistry* / Q000166:cytology; D014667:Vasopressins / Q000032:analysis*
D014667:Vasopressins; D010121:Oxytocin; D011388:Prolactin