Question

All hypophysiotropic hormones are peptide except
A. Corticotropin releasing hormone
B. Growth hormone inhibitory hormone
C. Somatostatin
D. Prolactin releasing inhibitory hormone

Answer 1

Hormones are informational molecules secreted by the endocrine cells in one part of the body in response to changes in external or internal environment are carried by blood to another part where they stimulate or inhibit specific physiological processes for the good of the body as a whole. In other words the hormones are chemical messengers that regulate the biological processes in the organisms.

Complete answer: The hormones may be classified into 4 categories : amino acid derivatives , peptides, proteins (polypeptides) and steroids.
Amino acid derivatives: The hormones epinephrine and norepinephrine from the adrenal medulla and thyroxine from the thyroid gland are derived from the acid tyrosine.
Peptides:
Short peptides : These hormones oxytocin and vasopressin from the posterior lobe of pituitary gland and melanocyte stimulating hormone from the intermediate lobe of the pituitary gland are short peptides.
Long peptides : The hormones insulin and glucagon from the pancreas, adrenocorticotropin from the anterior lobe of the pituitary gland, calcitonin from the thyroid gland, and parathormone from the parathyroid glands are long peptides.
Proteins (polypeptides). The gonadotrophic, somatotropic and thyrotropic hormones from the anterior lobe of the pituitary gland are proteins
Steroids. The hormones from adrenal cortex, testes, ovaries and placenta are steroids. They are synthesised from cholesterol. This shows that some cholesterol is essential for health.
Prolactin releasing inhibitory hormone is an amino acid derivative produced by hypothalamus. It inhibits the secretion of prolactin from the anterior pituitary.
So, the correct answer is option D. Prolactin releasing inhibitory hormone

Additional information :
Hypothalamus is composed of nervous tissue. It is connected with the anterior lobe of the pituitary gland by hypophysial portal blood vessels and with the posterior lobe of the pituitary gland by axons of its neurons. The portal vessels and axons pass through a stalk to the pituitary gland.

Note: The well known releasing and inhibitory hormones of hypothalamus and thyrotropin releasing hormone (TRH), adrenocorticotropin releasing hormone (A-RH), follicle stimulating hormone (FSH-RH), luteinising hormone releasing hormone (LH-RH), growth hormone (somatotropin) - releasing hormone(GH-RIH) or somatostatin, prolactin releasing hormone (P-RH), prolactin release inhibiting hormone (PR-IH).