Which of the following is NOT secreted in pancreatic tumour :
**Core Concept**
The question is testing knowledge of pancreatic islet cell tumors and their secretory products. Pancreatic tumors can secrete various hormones and peptides due to the presence of hormone-producing cells within the islets of Langerhans.
**Why the Correct Answer is Right**
The correct answer is a hormone or peptide that is not typically secreted by pancreatic islet cell tumors. For example, pancreatic tumors often secrete insulin, gastrin, glucagon, and vasoactive intestinal peptide (VIP), but they do not typically secrete thyrotropin-releasing hormone (TRH). TRH is primarily secreted by the hypothalamus and regulates thyroid-stimulating hormone (TSH) production in the pituitary gland.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because pancreatic tumors can secrete gastrin, leading to Zollinger-Ellison syndrome.
* **Option B:** This option is incorrect because pancreatic tumors can secrete insulin, leading to hypoglycemia.
* **Option C:** This option is incorrect because pancreatic tumors can secrete glucagon, leading to hyperglycemia.
**Clinical Pearl / High-Yield Fact**
Pancreatic islet cell tumors can be functional or non-functional. Functional tumors secrete excess hormones, leading to clinical syndromes such as Zollinger-Ellison syndrome or hypoglycemia, while non-functional tumors do not produce excess hormones and may present with non-specific symptoms.
**Correct Answer:** D. Thyrotropin-releasing hormone (TRH)